1. Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the present invention provides inflatable porous implants, such as grafts, stent-grafts, and bladders, as well as methods and kits for drug delivery.
Disorders of vessels and organs have created a need for prosthetic grafts or stent-grafts to repair or replace the function of the diseased vessels and organs. Of particular interest to the present invention are prosthetic devices that provide for the treatment of disease or injury that potentially compromises the integrity of a flow conduit in the body. For example, the prosthetic devices are useful in treating indications in the cardiovascular system, including thoracic and abdominal aortic aneurysms, arterial dissections (such as those caused by traumatic injury), etc. as well as indications in the digestive system (bile ducts, esophagus, and like structures in the gastrointestinal tract), respiratory system (bronchi, trachea, and the like), reproductive system (fallopian tubes, uterus, and the like), urinary system (urethral, ureteral, and the like), and other systems of the human body. The prosthetic grafts or stent-grafts reestablish or recreate the natural flow of the vessel or organ to be repaired, replaced, or bypassed.
While prosthetics grafts or stent-grafts have enjoyed some degree of success, enhancements to such implantable devices would be advantageous. In particular, one improvement is providing direct delivery of a therapeutic agent into the flow conduit in the body via the implantable prosthetic. In some instances, grafts for abdominal aortic aneurysms or other blood vessel aneurysms may suffer from complications such as thrombosis formation which may lead to occlusion of the graft; stent-grafts in general may provoke hyperplasia, which in turn may lead to failure of the graft. In such instances, the delivery of a therapeutic agent to treat or prevent such complications is especially useful.
To meet this need, various types of implantable devices have been designed to deliver agents directly into flow conduits in the body. Local delivery of therapeutic agents is advantageous over systemic administration for several reasons. First, local delivery enables appropriate dosages of the therapeutic agent to be achieved at a target site without subjecting other non-target vessels or organs to such agents. Second, the local concentration of the therapeutic agent can be much higher than can normally be achieved by systemic administration. Third, local delivery allows the therapeutic agent to focus on target tissue that might otherwise be slow to absorb the agent.
Direct administration of therapeutic agents primarily has been accomplished through the use of catheter injection or coated prosthetic devices. Direct administration of a therapeutic agent through a catheter typically requires that the catheter be in place in the body for the entire duration of drug delivery. As such, catheter injection treatment primarily is suited for short duration treatments. Coated prosthetic devices, such as stents, grafts, or other implants, are also widely utilized. While such coatings have achieved varying levels of success, some drawbacks are apparent. In particular, coating prosthetic devices involves a complex manufacturing process and in some instances the coating may be abraded off during assembly (e.g., passage of a stent through a delivery catheter or sheath) or deployment of the prosthetic. Another concern related to coated prosthetic devices is that the dosage amount, precision, and duration of drug delivery may also be limited by the coating itself, which typically represents a small fraction of a total mass of the implant.
For theses reasons, it is desirable to provide improved implantable devices and methods for delivering a therapeutic agent into a flow conduit in the body. In particular, it is desirable to provide improved implantable devices and methods that directly deliver larger, more precise doses of drugs over longer administration periods into the body. It is further desirable to provide implantable devices that are flexible and have a small profile for easy placement. It is still further desirable to provide integrated implantable devices that serve a mechanical or structural function in addition to drug delivery.
2. Description of the Background Art
Methods and apparatus for releasing active substances from implantable and other devices are described in U.S. Pat. Nos. 6,652,581; 6,652,575; 6,616,650; 6,613,084; 6,613,083; 6,613,082; 6,599,275; 6,554,857; 6,545,097; 6,537,195; 6,521,284; 6,471,980; 6,471,687; 6,409,716; 6,387,124; 6,379,382; 6,379,381; 6,364,856; 6,361,780; 6,358,276; 6,355,063; 6,355,055; 6,328,762; 6,316,522; 6,306,165; 6,254,632; 6,251,136; 6,240,616; 6,165,210; 6,096,070; 6,004,346; 5,972,027; 5,843,069; 5,609,629; 5,443,458; 5,411,550; 5,383,928; U.S. Publication Nos. 2003/0143330; 2003/0074048; 2003/0060871; 2003/0036794; 2003/0033007; 2003/0033004; 2003/0028243; 2003/0004565; 2002/0138048; 2002/0120326; 2002/0103527; 2002/0099434; 2002/0098278; 2002/0091440; 2002/0082685; 2002/0082682; 2002/0082680; 2002/0082552; 2002/0042645; 2002/0037145; 2002/0026235; 2001/0041928; PCT Publication Nos. WO 2004/004603 A1; WO 03/082360 A1; WO 03/043539 A1; WO 03/026713A1; WO 01/52914 A1; EP Patent Application Nos. EP 1 360 967 A1; EP 1 121 945 A1; EP 0 997 115 B1; EP 0 747 069 B1.
The full disclosures of each of the above-mentioned references are incorporated herein by reference.